Extreme pressure lubricant compositions



United States Patent 3,193,501 EXTREME PRESURE LUBRICANT CQMTOSETECNSHoward J. Matson, Harvey, 151., assignor to Sinclair Research, llnc.,Wilmington, Del., a corporation of Delaware No lirawing. Filed Apr. 2,1962, der. No. 184,544 3 Claims. (Cl. 252-463) The present inventionrelates to oleaginous base lubricants possessing excellent extremepressure and anti-wear properties.

Mineral oil and synthetic lubricants, in the form of greases orfree-flowing liquids, are called upon to ease friction and preventdamage to machinery operated at temperatures up to as high as about 450F. At elevated temperatures an internal combustion engine using theselubricants is an ideal oxidizing machine since the lubricant isviolently agitated in the presence of air for long periods of time. Inaddition the stability of the lubricants is further drastically reduceddue to contact with metallic surfaces which give up metallic particlesto the lubricant that act as powerful oxidation catalysts. Furthermore,water also causes corrosion of metallic surfaces and accentuatesoxidation of the lubricant. Aside from being stable under conditions ofuse the lubricant must exhibit anti-wear and load-carrying or extremepressure characteristics.

it has now been discovered that certain compounds when added in smalleffective amounts to oleaginous base lubricating oils provide alubricant composition with improved anti-wear and extreme pressurecharacteristics. The compounds added to the lubricants can berepresented by the following general formula:

I Jo-n s=P (can wherein X and Y are selected from the group consistingof chlorine and hydrogen and R is a saturated aliphatic hydrocarbonradical containing from 1 to 3 carbon atoms.

Any method known to the art for the preparation of these compounds canbe employed. A method for their preparation is described in US. PatentNo. 2,914,440 and involves the treatment of the 1:1 adduct of theappropriate chlorinated cyclopentadiene and diallyl sulfide with the0,0-dialkyl phosphorodithioate HSSP(OR) wherein ferred. The addition ofa small amount of an oxidation H inhibitor such as hydroquinone to thereaction mixture may be desirable. When the reaction is complete, themixture is taken up in a suitable solvent such as an aromatichydrocarbon and is Washed with a dilute aqueous solution of a base suchas sodium carbonate to remove any unreacted acid. The solution is thenWashed with water and dried and the solvent is distilled ofi.

The adducts of the chlorinated cyclopentadienes and diallyl sulfideuseful as starting materials in the preparation of the compounds of thisinvention can be prepared from the sulfide andhexachlorocyclopentadiene, 1,2,3,4,5-

3,13,51 Patented July 6, 1965 pentachlorocyclopentadiene, or1,2,3,4-tetrachlorocyclopentadiene. The latter two chlorinatedcyclopentadienes can be obtained, for example, by the catalytichydrogenation of hexachlorocyclopentadiene in the presence of a platinumgroup metal catalyst as described by McBee and Smith, Journal ofAmerican Chemical Society 77, 389 (1955). When hexachlorocyclopentadieneis used as the starting material, both X and Y are chlorine atoms in thefinal products. When 1,2,3,4,5-pentachlorocyclopentadiene is used, oneof X or Y is a chlorine atom and the other is a hydrogen atom. Whenl,2,3,4-tetrachlor0- cyclopentadiene is used, both X and Y are hydrogenatoms.

The reaction between the chlorinated cyclopentadiene and diallyl sufidecan be carried out with approximately equal molar ratios of reactants orwith an excess or either reactant. The temperature at which theadduction reaction is carried out is apparently not critical, buttemperatures in the range between about and C. are preferred. While thereaction takes place satisfactorily without a solvent, inert solvents ordiluents can be employed. The reaction is generally complete in a fewhours, and the product can be isolated by distilling off any solvent andfractionating the residue in vacuo.

The manner in which the compounds of this invention can be prepared isillustrated in the following examples:

EXAMPLE I Preparation of the l :1 adduct 0 diallyl sulfide and hexa- Vchlorocyclopentadiene Hexachlorocylopentadiene (136.34 g.; 0.5 mole) Washeated to a temperature of about 130 C. in a 3-necked round-bottomedflask fitted with a reflux condenser, mechanical stirrer, internalthermometer, and separatory funnel. Diallyl sulfide (57.10 g.; 0.5 mole)was added dropwise with stirring at such a rate as to maintain thetemperature at about 130 C. After the sulfide had been added, themixture was heated at C. for 1 hour. The cooled reaction mixture wasthen distilled in vacuo. The distillate was refractionated to give thedesired adduct having a boiling point of 144-145" C. at 0.3 mm.pressure.

EXAMPLE II Preparation 0 2,3,4,5,7,7-hexachl0r0-1,2,5,6-tetrahydr0- 2,5-methanobenzyl 2- 0,0-dimethylphosphorodithio propyl sulfide A mixtureof the 1:1 adduct (30 g.; 0.078 mole) of diallyl sulfide andhexachlorocyclopentadiene, 0,0-dimethyl phosphorodithioate (16 g.; 0.1mole), and 0.1 g. of hydroquinone was heated at 65 C. for 17 hours in around-bottomed flask fitted with a mechanical stirrer, internalthermometer, and reflux condenser. The temperature was then raised to 79C. for 8 hours. The cooled reaction mixture was dissolved in benzene andwashed first with 10% sodium carbonate solution and then with water. Thebenzene solution was dried over anhydrous sodium sulfate and filtered,after which the benzene was distilled off in vacuo, first with a Wateraspirator and then with a mechanical vacuum pump. The brown residue wasfiltered through Super-Cel (a diatomaceous silica filtering aid) to give28 g. of 2,3,4,5,7,7-hexachloro-1,2,5,6- tetrahydro-2,S-methanobenzyl2-(0,0-dimethylphosphorodithio)-propyl sulfide, a viscous oil having anindex of refraction (D line) at 24 C. of 1.5746. Analysis forC13H17C1602PS3I Theory-Cl, P, S 17.65%. FoundCl, 40.03%; R, 5.23%; S,17.01%.

Examples of other compounds which fall within the scope of thisinvention and can be prepared in the manner described above are asfollows: 2,3,4,5,7-pentachloro- 1,2,5,6 tetrahydro 2,5-methanobenzyl2-(0,0-dimethylanobenzyl 2-(0,0-di-n-propylphosphorodithio.)propyl sul-V fide; 2,3,4,5,7,7 hexachloro 1,2,5 ,6-tetrahydro-2,5-methanobenzyl2-(0,0-diisopropylphosphorodithio)propyl sulfide.

The lubricating oil base stock used in the present invention is oflubricating viscosity and can be, for instance, a solvent extracted orsolvent refined oil obtained in accordance with conventional methods ofsolvent refining lubricating oils. Generally, lubricating oils haveviscosities from about 20 to 250 SUS at 210 F. The base oil may bederived from paraffiiiic, naphthenic, asphaltic or mixed base crudes,and if desired, a blend of solvent-treated Mid- Continent neutrals andMid-Continent bright stocks may be employed. The oils may be thickenedto grease consistency. 0 I a g The base oil of the fluid lubricant orgrease may be a synthetic oil of lubricating viscosity. One type ofsynthetic oleaginous base used ispan. ester synthetic oil of lubricatingviscosity which consists essentially of carbon, hydrogen andoxygen, e.g.di-2-ethylhexyl sebacate; Various of these lubricating materialshave-been described in theliterature and generally their viscosityranges from the light to heavy oils, e.g. about 50 SUS atv 100 F. to 250SUS at 210 F. and preferably 30 to 150 SUS at 210 F.

These esters are of improved thermal stability, low acid number and highflash and fire points. The complex esters, diesters, monoesters andpolyesters may be used alone or to achieve the most desirable viscositycharacteristics, complex esters, diesters and polyesters may be blendedwith each other or with naturally-occurring esters like castor oil toproduce lubricating compositions of wide viscosity ranges which can betailorunade to meet various specifications. This blending'is performed,for example, bystirring together a quantity of diester and complex esterat an elevated temperature, altering the proportions of each componentuntil the desired viscosity is reached.

These esters are prepared fundamentally by theaction of acids onalcohols. The mere mixture of an alcohol and acid at the propertemperature will react to produce an equilibrium mixture which includesthe, monoester. The same is true for the reactions of organic dibasicacids and glycols to produce synthetic lubricant polyester bright stock.The die'sters are frequently of the type alcoholdicarboxylicacid-alcohol, While complex esters are generally of the type XYZY-X inwhich X represents a monoalcohol residue, ,Y, represents a dicarboxylicacid residue and Z represents a glycol residue and the linkages areester linkages. especially adaptable to the conditions to which turbineengines are exposed, since they can be formulated to give a desirablecombination of high flash point, low pour point, and high viscosity atelevated temperature, and need contain no additives which might leave aresidue upon volatilization. In addition, many complex esters have shownThese esters have been found-to be" good stability to shear. Greaseswhich use these esters as the oleaginous base also have most of thesecharacteristics. 1

Suitable monoand dicarboxylic acids used to make synthetic esterlubricant bases can be branched or straight chain and saturated orunsaturated and they frequently containfrom about 2 to 12 carbon atoms.The alcoholS 4 usually contain from about 4 to 12 carbon atoms. Ingeneral, the useful glycols include the aliphatic monoglycols of 4 to 20or 30'carbon atoms, preferably 4 to 12;

The compositions of this invention incorporate a small, minor amount ofthe above described additives suflicient to provide the base oil oflubricating viscosity which is the major portion of the composition withimproved anti-wear and extreme pressure properties. This amount isgenerally about 0.01 to 15 or 20% or more depending on the particularbase oil usedand its application. The preferred concentration should bethe minimum amount to give the desired properties for the particularapplication and usually will be about 0.2 to 5%. In some cases where oilsolubility might limit the amount of additive employed, dispersants maybe used to increase the concentration. In these cases, it has been foundthat increased solubility is best obtained iii highly refined oils bydissolving the dispersant in the oil before dissolving the additive. 7Materials normally incorporated in lubricating oils and greases toimpart special characteristics can be added to the composition of thisinvention. These include corrosion inhibitors, additional extremepressure agents, antiwear agents, etc. The amount of additives includedin the composition usually ranges from about 0.01 weight percent up toabout 20 or more weight percent, and in generalthey can be employed inany amounts desired as long as the composition is not undulydeleteriously afiected.

The following example is included to illustrate the ad-. vantages of thecompounds or" the present composition in lubricant compositions.

. EXAMPLE I v v 1% by weight of 2,3 ,4,5,7,7-hexachloro-1,2,5,6-tetrahydro 2,5 methanobenzyl2-'(0,0-dimethylphosphodithio) propylsulfide, the product of Example IIabove, was incorporated in an oil blend (defined in Table I below) andthe lubricant composition was subjected to the Falex breakdown test andthe Shell 4-ball extreme pressure and wear tests. For comparison, thebase oil without the additive of the present invention was also tested.The results of the tests are shown in Table I.

TABLE I Additive cone, wt. percent I II Base Oil Reslilt? B k V 7None 1. O 0. ex rea down Test, lbs 1 250 3 000 Shell 4-B all Wear Test,sear diam., mm. (7 kg. 2hrs.,, 11 C., 640 gms.) 0.57 0.28

- {Base o l is a blend of 70% ot a solvent refined Mid-Continent brightstock having a viscosity 01120 S U S at 210 F. and a viscosity index ofand 30% of a solvent refined Mid-Continent; neutral oil having aviscosity of 200 SUS at F. and a viscosity index of 85.

EXAMPLES II AND in erties to the composition of a compound having thestructural formula:

wherein X and Y are selected from the group consisting of chlorine andhydrogen atoms and R is a saturated hydrocarbon radical containing from1 to 3 carbon atoms. 15

2. The composition of claim 1 wherein the base oil is a mineral oil oflubricating viscosity.

3. The composition of claim 2 wherein the compound is in the range ofabout 0.2 to 5% by weight of the lubricant composition.

5 References Cited by the Examiner UNITED STATES PATENTS 2,223,793 12/40Peel-y 25246.7 2,226,420 12/ 40 Badertscher et a1 252-46.7 10 2,494,3321/50 Cyphers 252-467 2,760,937 8/56 McDerrnott 252-46] 2,881,196 4/59Fields 25246.7 X 2,914,440 11/59 Utermohlen 260461.112 2,970,110 l/61Fields 252-46.7 X 2,991,250 7/61 Socolofsky 25246.7 3,020,305 2/62 Chupp25246.7 X

DANIEL E. WYMAN, Primary Examiner.

1. AN OLEAGINOUS LUBRICANT COMPOSITION ESSENTIALLY OF A BASE OIL OFLUBRICATING VISCOSITY AND AN AMOUNT SUFFICIENT TO GIVE IMPROVED EXTREMEPRESSURE PROPERTIES TO THE COMPOSITION OF A COMPOUND HAVING THESTRUCTURAL FORMULA: